I have a plot, I have a plot

I might have lost then plot figuratively speaking, but now I finally have a plot I think I can work on. Actually to be honest the minute I though of the plot several other ones made their presence known, but you can't really argue with that now can you, at least if this one falls through I have some other choices.
If I go with my newly cooked up story I'll be doing something completely different from what i have been doing before. Every year I've been doing Regency based stories, and now I'm going contemporary with a thriller/horror/suspense story.
Gaaaah, maybe this isn't a good idea, after all i have no idea that I'm doing, at least if I migrated over to Fantasy i would be writing about something I enjoy reading about. Horror though is definitly not soemthing you will find in my bookshelf, not that i don't like it, it's just I'm so easily scared :)

Thinking about it though I could quite easily convert the story to a horror/fantasy, that might be fun. Good Gods I should stop writing and thinking, I'm just confusing myself now.
Maybe a little more thinking about it will be good, work out how it could be in the different genres, also i only have an idea, so need to form the plot better :)

Time limit for forming basic plot - 16:00 today, which gives me 5 hours :)